System and device for preventing restenosis in body vessels

ABSTRACT

The present invention relates to a system and device for preventing stenosis and/or restenosis after an invasive procedure in a body vessel or cavity having an inner wall surface, the system comprising inserting a device coated with a growth arresting, lipid-derived, bioactive substance at a desired location along the inner wall surface of the body vessel or cavity.

RELATED APPLICATIONS

[0001] This application is a continuation of co-pending U.S. applicationSer. No. 09/679,715 filed on Oct. 5, 2000, which claims priority under35 U.S.C. §119(e) to U.S. Provisional Application No. 60/157,960 filedon Oct. 6, 1999.

BACKGROUND OF THE INVENTION

[0002] Restenosis persists as a major complication in the maintenance ofvessel patency after percutaneous transluminal angioplasty in coronary(PTCA) and other vessels. Restenosis is a consequence of multiplefactors, including vessel recoil, negative vascular remodeling, residualplaque burden, and neointimal hyperplasia. Neointimal hyperplasiareflects the migration and proliferation of vascular smooth muscle (VSM)cells with subsequent deposition of extracellular matrix components atthe site of injury. Considerable evidence indicates that, in restenosis,growth factors stimulate the VSM cells to proliferate, resulting in athickening of the tunica intima. Nearly 40% of all patients developsignificant luminal narrowing within 6 months after angioplastyprocedures. Consequently, despite the initial therapeutic benefits ofangioplasty, within a few months after surgery, blood flow through theaffected vessels can again become compromised. Conventional therapies,which include angiotensin-converting enzyme inhibitors, anticoagulants,and statins, are ineffective in preventing or reducing neointimalhyperplasia after stretch injury. Endovascular radiation therapy hasshown some success in both animal and human trials, yet the long-termdeleterious effects of this therapy on the artery have not beenadequately evaluated.

[0003] Ceramide is a growth arresting metabolite of sphingomyelin, amajor lipid component of the cell membrane. More specifically, ceramideis a complex lipid which can be found in the plasma membrane. It isproduced by the breakdown of sphingomyelin by sphingomyelinases, aprocess which is enhanced during inflammatory cytokine (IL-1,TNF and CD95 ligand) induced growth arrest and/or cell death. It appears thatceramide acts as a bioactive which can mediate vascular smoothmuscle-growth arrest and/or apoptosis by the direct activation ofcertain kinases. It is hypothesized that direct and immediate deliveryof a cell-permeable ceramide or analog via the balloon tip of anembolectomy catheter or chronic delivery via coating of a stent wouldreduce the VSM proliferation that is observed in restenosis afterangioplasty.

[0004] It is known that ceramide inhibits VSM proliferation byactivating c-jun N-terminal kinase (JNK) while suppressing extracellularsignal regulated kinase (ERK) and protein kinase B (PKB) in vitro. Yet,the possibility that a cell-permeable ceramide could diminish VSMproliferation in vivo has until now not been tested. The use ofcatheters to open diseased arteries, body vessels or cavities is alsoknown, as in e.g., U.S. Pat. No. 5,599,307, herein incorporated byreference. However, the prior art therapeutic devices themselves inducea significant amount of regrowth of VSM in the artery, which leads tosecondary blockages or occlusions (i.e., restenosis).

SUMMARY OF THE INVENTION

[0005] The present invention relates to a system and device forpreventing stenosis (narrowing) and/or restenosis (renarrowing) after aninvasive procedure (e.g., vascular or surgical intervention) in a bodyvessel or cavity having an inner wall surface, the system comprisinginserting a device coated with a growth-arresting, lipid derived,bioactive substance at a desired location along the inner wall surfaceof the body vessel or cavity. By delivering the substance directly andimmediately to the site of action, subsequent regrowth of smooth musclecells is prevented, thus overcoming the inflammatory response whichoccurs due to the body's dealing with the original surgicalintervention, e.g., angioplasty.

[0006] In a preferred embodiment, the present invention discloses aceramide treatment which significantly reduces neointimal hyperplasiainduced by balloon angioplasty in carotid arteries. It is demonstratedthat ceramide ameliorates stenosis by decreasing the trauma-associatedphosphorylation of extracellular signal regulated kinase (ERK) andprotein kinase B (PKB). As described below, it has been demonstratedthat the utility of cell-permeable ceramide is a novel therapy forreducing restenosis after balloon angioplasty.

[0007] In another preferred embodiment, the present invention relates toa method of preventing and/or treating stenosis at a site along a bodyvessel comprising administering to the site a lipid-derived bioactivecompound which inhibits cell proliferation, wherein the compound isselected from the group consisting of ceramide or derivatives thereof,dimethyl sphingosine, ether-linked diglycerides, ether-linkedphosphatidic acids and sphinganines.

[0008] In another preferred embodiment, the present invention relates toa method of preventing and/or treating hyperplasia at a site in a bodylumen, comprising administering to the site an amount of a lipid-derivedbioactive compound which inhibits cell proliferation without inducingsignificant apoptosis, wherein the compound is selected from the groupconsisting of ceramide or derivatives thereof, dimethyl sphingosine,ether-linked diglycerides, ether-linked phosphatidic acids andsphinganines.

[0009] In another preferred embodiment, the present invention relates toan intraluminal system for preventing and/or treating neointimalhyperplasia at a site in a vessel. The system comprises a pharmaceuticalformulation comprising a lipid-derived bioactive compound capable ofinhibiting phosphorylation of a kinase, and a pharmaceuticallyacceptable carrier; and a device adapted for intraluminal delivery ofthe pharmaceutical formulation to the site.

[0010] In another preferred embodiment, the present invention relates toa method for preventing and/or treating hyperplasia at a site in a bodylumen, comprising administering to the site a growth-arresting,lipid-derived bioactive compound which inhibits phosphorylation of agrowth factor-induced extracellular signal regulated kinase (ERK) and/ora protein kinase B (PKB).

[0011] The growth-arresting, lipid-derived bioactive compound inaccordance with the various embodiments of the present invention ispreferably selected from the group consisting of ceramide or derivativesthereof, dimethyl sphingosine, ether-linked diglycerides, ether-linkedphosphatidic acids and sphinganines. More preferably, the compound isceramide or a derivative thereof, that contains a 2-10 carbonshort-chain fatty acid at SN-2 position. Most preferably, the ceramideor derivative thereof is a C₆-ceramide.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a cross-sectional view of a balloon catheter coated withthe growth arresting lipid-derived bioactive substance.

[0013] FIGS. 2A-F are results of experiments evaluating the therapeuticpotential of ceramide-coated embolectomy catheters upon restenosis afterballoon angioplasty.

[0014] FIGS. 3A-D show results of experiments conducted to quantifyceramide transfer between the balloon and the carotid artery.

[0015] FIGS. 4A-F show the effects of ceramide treatment on VSM cellgrowth.

[0016] FIGS. 5A-C show the evidence from in vitro studies that ceramidearrests cell growth.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] The present invention relates to a system and device forpreventing stenosis and/or restenosis after an invasive procedure in abody vessel or cavity having an inner wall surface, the systemcomprising inserting a device coated with a growth arresting,lipid-derived, bioactive substance at a desired location along the innerwall surface of the body vessel or cavity. By delivering the substancedirectly and immediately to the site of action, subsequent regrowth ofsmooth muscle cells is prevented, thus overcoming the inflammatoryresponse which occurs due to the body's dealing with the originalsurgical intervention, e.g., angioplasty. The devices which may beenhanced with the treatment of the present invention include, but arenot limited to, simple catheter/simple (one) balloon designs, a dualballoon catheter design, or stents. Microporous catheter design,infusion catheter design, rotary atherectorny device design, polymeric(e.g., polyacrylic acid) coated balloon designs, bioabsorbable coatingdesigns, stent covers and perivascular matrices may all possibly beenhanced as well.

[0018] By “growth arresting,” it is meant that the cells (e.g., vascularsmooth muscle cells) are no longer responsive to growth factors orcytokines released from damaged tissue. By “lipid-derived,” it is meantthat the substances are formed for the metabolism of lipids inmembranes. Therefore, there is minimal immunologic/inflammatory responseof the body to these compounds. Finally, by “bioactive,” it is meantthat the agents transduce information from the outside membranes of thecell to the nucleus where new genes are activated or inactivated tochange the phenotype of the cell. Examples of such antimitogenicmaterials include ceramides and ceramide derivatives, e.g.,cell-permeable analogs and forms which are subject to diminishedmetabolism. These include, but are not limited to, derivatives of theSN-1 position including 1-chloro and 1-benzoyl ceramides, which wouldnot be subject to phosphorylation at this position, as well asderivatives at the SN-2 position (amide linkage), such as amethylcarbamate group or a 2-O-ethyl substituent, which would not besubject to degradation by ceramidases. In addition, cell-permeable formsof these ceramide analogs can be utilized. Examples of thesecell-permeable ceramides and/or derivatives contain 2-10 carbons andhave short-chain fatty acids at the SN-2 position (C6 ceramide).

[0019] Other examples of growth arresting, lipid-derived, bioactivesubstances include, but are not limited to, dimethyl sphingosine,ether-linked diglycerides, ether-linked phosphatidic acids, andsphinganines.

[0020] The device to be coated is preferably dipped in a vehicleincluding DMSO/ethanol, the actual coating process performed in asterile environment so as to result in an effective amount of coatingmaterial remaining on the device. Devices can then be subjected toradiation sterilization. Ceramide-coated devices may be optimized fordelivery from hydrophobic and hydrophilic coatings, as well asabsorbable or polymeric matrices.

[0021] As shown in FIG. 1, which displays an embodiment containing acatheter and single balloon design, catheter 14 with associated balloon10 is inserted into lumen 13, surrounded by artery wall 12. Catheter tip15 and balloon 10 are coated with the growth-arresting, lipid-derivedbioactive substance 11 for use during a particular treatment, leading toopening of clogged and/or narrowed vessels that impede blood flow.

[0022] In a further preferred embodiment, the present invention relatesto balloon catheters and/or stents coated with growth-arresting,lipid-derived, bioactive substances and a system for preventingrestenosis after an invasive procedure in a body vessel or cavity havingan inner wall surface, the system comprising the steps of:

[0023] (a) inserting a therapeutic device (e.g., balloon on anembolectomy catheter, stent, and/or rotary atherectomy device) to reducethe narrowing of arteries in a desired location along the inner wallsurface, the device coated with a growth-arresting, lipid-derived,bioactive substance or derivative thereof;

[0024] (b) inflating the balloon on the embolectomy catheter or placingthe stent in a portion of the vessel or cavity with damaged or diseasedtissue;

[0025] (c) (i) supplying material (directly and immediately by inflationof the balloon, or at a sustained rate via the stent) to and (ii)removing plaque or debris from the diseased portion and/or serving as ascaffolding device; and

[0026] (d) providing a treatment to the diseased or occluded portion ofthe vessel or cavity.

[0027] Such steps will prevent secondary regrowth of the damagedvascular smooth muscle tissue, while still allowing wound healing.

[0028] Experiments were designed to evaluate the therapeutic potentialof ceramide-coated embolectomy catheters upon restenosis after balloonangioplasty. Initial studies assessed the extent of restenosis in rabbitcarotid arteries after balloon angioplasty as a function of time.Animals were sacrificed 1, 2, 4 and 6 weeks after balloon injury. Markedneointimal hyperplasia was observed as early as 1 week and peaked at 4weeks (FIG. 2A). Sham-treated carotid arteries showed no signs ofneointimal hyperplasia at anytime. The medial vascular smooth musclelayer also showed distinct hypertrophic injury after balloon treatment.Based upon these results, the effects of ceramide upon dynamicrestenotic VSM growth, 2 weeks post balloon injury were investigated.FIGS. 2B-E illustrate hematoxylin and eosin stained cryostat sections ofrabbit carotid arteries. In addition to the sham-treated control artery(FIG. 2B), the three treatment groups included a vehicle-treated balloon(FIG. 2C, a C6-ceramide-coated balloon (FIG. 2D) and adihydro-C6-ceramide (an inactive, inert substance)-coated balloon (FIG.2E). Surprisingly, the C6-ceramide treatment significantly reduced theneointimal hyperplasia induced by balloon angioplasty. A quantitativeanalysis revealed that ceramide inhibited the balloon-induced neointimalformation by 92% as reflected in the reduction of the neointimal/medialratio (FIG. 2F). In contrast, dihydro-C6-ceramide, an inactive analogueof C6-ceramide, did not reduce restenosis after balloon injury. Thus,the inhibitory effect requires bioactive ceramide and cannot beduplicated using structurally similar but inactive lipids. Furthermore,it may be theorized that the effects of ceramide are due to biochemicalactions and not lipophilic properties.

[0029] Specifically, in FIG. 2, C6-ceramide but not dihydro-C6-ceramideblocked neointimal hyperplasia after balloon angioplasty in rabbitcarotid arteries. Initial experiments optimized the methods to inducerestenosis after angioplasty in carotid arteries from New Zealand whiterabbits. Twenty-one rabbits were divided into three experimental groups,undergoing either balloon angioplasty with a vehicle-treated catheter, aC6-ceramide-treated catheter or a dihydro-C6-ceramide-treated catheter.Each rabbit underwent identical procedures to denude the common carotidartery of endothelium and establish the cellular conditions to promoterestenosis. The right common carotid served as the sham control whilethe left carotid served as the experimental side. There were nosignificant differences between sham control, vehicle control orceramide-treated arteries in terms of either tissue wet weight orcellular protein content. FIG. 2A represents the time course ofrestenosis after angioplasty, while FIGS. 2B-2E depict representativeH/E stained sections. The upper left panel (FIG. 2B) depicts asham-treated control artery while the upper right panel (FIG. 2C) showsan artery treated with a DMSO/ethanol (1:1, v/v)-coated balloon. Thebottom left panel (FIG. 2D) shows an artery treated with aC6-ceramide-coated balloon and the bottom right panel (FIG. 2E) anartery treated with dihydro-C6-ceramide, a biologically inactive form ofceramide. The scale for these photomicrographs is 200 microns. FIG. 2Fquantifies the extent of restenotic lesions.

[0030] The inability of experimentally effective therapies to succeed inclinical trials is often the consequence of sub-optimal doses oftherapeutics being delivered to the site of injury for the appropriateduration. Moreover, the efficacy of therapy may be a consequence ofbiomechanical force transferring ceramide from the inflated balloon tothe site of vascular lesions. Therefore, experiments were conducted toquantify ceramide transfer between the balloon and the carotid artery;the pharmacokinetics of ceramide transfer and delivery from the ballooncatheter to the damaged artery was assessed. Using [³H]C6-ceramide as atracer, it was calculated that 70±10 nmol of C6-ceramide was applied tothe balloon as a gel from a solution of 5 μmol of C6-ceramide. FIG. 3Ashows that, after insertion and inflation, 12±2 nmol remained on theballoon. This translates to roughly 58 nmol of C6-ceramide beingtransferred from the balloon catheter during the angioplasty procedure.To test whether inflation of the balloon within the carotid artery wasessential for optimal transfer of the ceramide, the surgical procedurewas performed using noninflated balloons. The recovered ceramide mass onthe inserted but noninflated balloon was 14±3 nmol. Rabbit carotidarteries treated with radiolabeled lipid were homogenized, and lipidproducts were separated by thin-layer chromatography (TLC) (FIG. 3A).The mass of intact ceramide isolated 15 minutes after angioplasty was2.7±0.4 nmol for inflated balloon treatments and 0.7±0.2 nmol fornoninflated balloon treatments. The amount of ceramide recovered fromexcised tissues did not differ significantly from the amount of ceramidetransferred to the tissue as a consequence of balloon inflation. As thetransferred ceramide was initially delivered to 0.0365 cm³ of carotidartery luminal volume, the effective concentration of ceramide at thesite of balloon injury is estimated to be 1.5 mmol/L. Thus, an effectiveand reproducible dose of ceramide can be delivered to the damaged arteryas a consequence of the balloon inflation.

[0031] In situ autoradiography was utilized to document arterialpenetrance for [³H]C6-ceramide transferred from the balloon catheterafter angioplasty (FIGS. 3B through 3D). Compared with unlabeledarteries (panel B), [³H]C6-ceramide was observed throughout the mediallayers of the artery 15 minutes after angioplasty (panel C). Thisincrease in pixel intensity reflects an increase in intact ceramide, asat this time point 89±4% of the radiolabel comigrates with authenticC6-ceramide standards. Pixel intensity was more intense in inflated(panel C) versus noninflated (panel D) arteries. Expressed as pixeldensity per square millimeter for 10 randomly selected blocks withbackground values subtracted, medial staining was increased 4.7±0.2-foldfor ceramide-coated inflated versus noninflated balloons. Again, thissupports the conclusion that balloon inflation leads to maximal deliveryand penetrance. Thus, a lipid-coated balloon delivers a therapeutic doseof ceramide to tissues underlying the site of vascular stretch injury,and demonstrates that a short-term application of cell-permeableceramide is sufficient to completely penetrate injured arteries and toreduce intimal proliferation despite an inflammatory milieu.

[0032] The degradation of the rapidly intercalated radiolabeled ceramideby TLC was also assessed. For the 15-minute postangioplasty time point,89±4% of the TLC-separated lipid comigrated with authentic C6-ceramidestandards. This corresponded to a recovered mass of 2.7±0.4 nmol ofceramide. At 60 minutes after angioplasty, 1.3±0.6 nmol of ceramide wasrecovered. Thus, 50% radiolabel can still be recovered as intactceramide in 1 hour. This decrease in ceramide mass corresponded to anincrease in TLC-separated gangliosides and cerebrosides but notsphingosines.

[0033] It is noted that infusion-type catheters have the advantage todeliver ceramide in a BSA vehicle at a discrete dose to the site ofarterial injury. It was thus determined whether ceramide delivered bysolution using an infusion-type catheter is also effective in reducingrestenosis as ceramide delivered using a catheter with a gel coatedballoon tip. The balloon at the tip of a 4F arterial biTumen irrigationembolectomy catheter was inflated to a diameter equivalent to that ofthe earlier experiments. Three infusions of 10 μM C6-ceramide for 1minute each reduced restenosis after balloon angioplasty by 39%.Dihydro-C6-ceramide at an equivalent dose had no effect upon restenoticlesions. These studies further support the novelty and efficacy ofceramide-coated balloon catheters as intra-arterial site-specificdelivery devices.

[0034] To prevent thrombus formation, patients routinely receiveanti-coagulants prior to percutaneous transluminal coronary angioplasty.Thus, the consequences of anticoagulation therapy on the effectivenessof ceramide therapy were investigated. Neither ceramide- norvehicle-treated balloon angioplasty induced thrombus formation. Lovenox(a low molecular weight heparin), administered subcutaneously (2.5mg/kg) for 7 days postsurgery, did not by itself diminish restenosis anddid not augment ceramide-induced inhibition of restenosis, suggestingthat ceramide treatment is equally effective in both anti-coagulated anduntreated protocols.

[0035] The effects of ceramide treatment upon VSM cell growth in vivowere also investigated. Immunohistochemical techniques were employed toidentify VSM using smooth muscle cell-specific actin antibody (FIGS.4A-B) and cell growth using proliferating cell nuclear antigen (PCNA)antibody (FIGS. 4C-F). The positive staining with the actin antibodyindicates that VSM was a major component of balloon injury-inducedneointimal formation (FIG. 4B). Also, this photomicrograph showsdramatic balloon angioplasty-induced ruffling and dispersion of VSM inthe medial layer. PCNA is synthesized in early G1 and S phases of thecell cycle, and thus can be used as a marker for cell proliferation. InFIGS. 4C-F, representative photomicrographs depicting PCNA positivestaining are shown for control, balloon-injured, ceramide-treated anddihydro-ceramide-treated carotid arteries, respectively. The percentageof PCNA positive cells in balloon-injured arteries (2.8%±0.1%) wasdramatically increased compared with control vessels (0.2%±0.1%).C6-ceramide (0.6%±0.2%), but not dihydro-C6-ceramide (1.9%±0.3%)diminished the number of PCNA positive cells in the neointimal layer butnot in the medial layer of the carotid artery. These data demonstratethat ceramide reduces neointimal hyperplasia by diminishing thepercentage of VSM that enters the cell cycle after trauma to the vesselwall.

[0036] Specifically, in FIG. 4, ceramide-treated catheters reduced PCNAexpression in vascular smooth muscle cells after angioplasty. Smoothmuscle actin expression was analyzed by immunohistochemistry utilizing amonoclonal anti-alpha smooth muscle antibody, and PCNA positive cellnumbers were assessed with a primary mouse monoclonal IgG2a antibody forPCNA. Stain control slides substituted the primary antibody withnonspecific mouse IgG and did not reveal any specific or selectivestaining. These immunohistochemical micrographs are representative offour separate experiments. Panels A-B reflect smooth muscle actinstaining for control and balloon-injured arteries, respectively, whilepanels C-F represent PCNA staining for control, balloon-injured,ceramide-coated balloon-injured and dihydro-ceramide-coatedballoon-injured carotid arteries, respectively. The scale for thesephotomicrographs is 200 microns.

[0037] Evidence from in vitro studies shows that ceramide arrests cellgrowth by inhibiting the growth factor-induced extracellular signalregulated kinase (ERK) cascade and possibly by inhibiting the proteinkinase B (PKB) cascade. Thus, to elucidate mechanisms by which ceramideprevents restenosis, the phosphorylation states of ERK2 and PKBA wereinvestigated using freshly excised carotid arteries after angioplasty(FIG. 5). Phosphorylation of ERK2 and PKBA were increased at 15 minutesand 24 hours post-balloon injury. The sustained phosphorylation of thesekinases most likely reflects continuous remodeling of damaged arteries.Immediately after ceramide treatment, the phosphorylation states ofthese kinases were reduced below basal activation levels. Thus, acuteceramide therapy may directly modulate kinases or regulate putativeceramide-activated protein phosphatases that down-regulate thesesignaling pathways.

[0038] Specifically, in FIG. 5, ERK2 and PKBa phosphorylation werediminished after ceramide-coated balloon angioplasty in rabbit carotidarteries. Panel A depicts a representative Western blot for ERK-2 andPKBa probed using phosphorylation-specific antibodies. Lysates fromNIH3T3 cells treated with or without PDGF were used as positive andnegative controls, respectively. This immunoblot is representative ofsimilar experiments using a total of 8 animals. Panels B-C quantifiesthe immunoblot data.

[0039] It has been previously demonstrated that C6-ceramide mimicked theeffect of IL-1 to inhibit both tyrosine kinase receptor- and G-proteinreceptor-linked mitogenesis in A7r5 aortic smooth muscle cells and ratglomerular mesangial cells. Ceramide treatment correlated with growtharrest at G₀G₁ and not apoptosis in these smooth muscle-like pericytes.The present invention shows that C6-ceramide does not induce significantapoptosis in primary VSM isolated from rabbit carotid arteries asassessed by fluorescence-activated cell sorting after propidium iodidestaining using a previously described doublet discrimination protocol.Specifically, primary rabbit VSM treated with 5 μM C6-ceramide ordihydro-C6-ceramide for either 24 or 40 hours showed less than 1%apoptotic cell death. As a control, okadaic acid treatment (100 nM)significantly induced apoptosis after 24 hours (52%) and 40 hours(69%±2%). Thus, the therapeutic efficacy of cell-permeable ceramide inrestenosis includes its ability to arrest VSM growth without inducingsignificant apoptosis.

[0040] Other cell-permeable ceramide derivatives can also limitneointimal hyperplasia. Derivatives of ceramide, in which theamide-linked fatty acyl chain is replaced with dimethyl moieties, e.g.,dimethylsphingosine, are also effective in limiting angioplasty-inducedinjury.

[0041] Although altered ceramide metabolism has been implicated inatherosclerosis, diabetes mellitus and cancer, ceramide analogues havenot yet been considered as therapeutics for proliferative vasculardiseases. Increased concentrations of lactosyl- and glyco-ceramideconjugates at the expense of endogenous ceramide were noted in models ofatherosclerosis and diabetes mellitus, and this diminished level ofceramide correlated with VSM proliferation and vasoconstriction. Withendogenous levels of ceramide depleted, it is logical to consider theuse of exogenous ceramide analogues as antimitogenic agents. The presentinvention demonstrates that ceramide is a strong candidate forpreventing restenosis after angioplasty. The present invention is alsoanticipated to be effective in treating stenosis of e.g., coronary,renal and femoral arteries, and may have venuous uses as well, e.g., asa calibrated portal caval shunting or unclogging blocked saphenous veinsused for coronary bypass. Furthermore, the present invention may haveuses in such areas as diabetic retinopathy, where smooth muscle-likecells are activated and proliferate in front of the retina, resulting inblindness. Locally delivered ceramide can also be used to potentiallytreat dysregulated smooth muscle growth in stenosis of vascular accesslines after chronic dialysis. In addition to delivering these drugs onthe tips of balloon catheters, through infusion ports, or coated onstents, these anti-mitogenic sphingolipid derivatives can be deliveredas components of conventional or cationic liposomal vectors, potentiallyaugmenting the efficacy of gene transfer and targeting strategies.

[0042] Thus, the present invention demonstrates inhibition of smoothmuscle cell growth at the site of injury, when ceramide or other growtharresting, lipid-derived derivatives are locally administered by coatingballoons and stents. In addition, ceramides or other growth arresting,lipid-derived, bioactive substances can be delivered at fixed dosagesvia infusion or microporous catheter designs. Infusion catheters deliverthe substance through a port distal to the inflated balloon. Microporouscatheters deliver the substance via minute pores on the balloon surface.Also, the materials of the present invention can be delivered via adouble balloon, infusion port, catheter design to deliver substance tothe damaged arterial wall, isolated between the two inflated balloons.According to a preferred embodiment of the present invention,C6-ceramide, a cell permeable ceramide, inhibits smooth muscle cellproliferation at the angioplasty site. Alternatively, othercell-permeable ceramide derivatives can also limit neointimalhyperplasia. Derivatives of ceramide, in which the amide-linked fattyacyl chain is replaced with dimethyl moieties, are also effective inlimiting angioplasty-induced injury.

What is claimed is:
 1. A method of preventing and/or treating stenosisat a site along a body vessel comprising administering to said site alipid-derived bioactive compound which inhibits cell proliferation,wherein said compound is selected from the group consisting of ceramideor derivatives thereof, dimethyl sphingosine, ether-linked diglycerides,ether-linked phosphatidic acids and sphinganines.
 2. The method of claim1, wherein said lipid-derived bioactive compound is ceramide or aderivative thereof, that contains a 2-10 carbon short-chain fatty acidat SN-2 position.
 3. The method of claim 2, wherein the ceramide orderivative thereof is a C₆-ceramide.
 4. The method of claim 3, whereinthe C₆-ceramide is administered at a dose sufficient to inhibit cellproliferation without inducing significant apoptosis.
 5. A method ofpreventing and/or treating hyperplasia at a site in a body lumen,comprising administering to said site an amount of a lipid-derivedbioactive compound which inhibits cell proliferation without inducingsignificant apoptosis, wherein said compound is selected from the groupconsisting of ceramide or derivatives thereof, dimethyl sphingosine,ether-linked diglycerides, ether-linked phosphatidic acids andsphinganines.
 6. The method of claim 5, wherein said growth-arresting,lipid-derived bioactive compound is ceramide or a derivative thereof,that contains a 2-10 carbon short-chain fatty acid at SN-2 position. 7.The method of claim 5, wherein the ceramide or derivative thereof is aC₆-ceramide.
 8. An intraluminal system for preventing and/or treatingneointimal hyperplasia at a site in a vessel, comprising: apharmaceutical formulation comprising a lipid-derived bioactive compoundcapable of inhibiting phosphorylation of a kinase, and apharmaceutically acceptable carrier; and a device adapted forintraluminal delivery of said pharmaceutical formulation to said site.9. The intraluminal system of claim 8, wherein said compound is selectedfrom the group consisting of ceramide or derivatives thereof, dimethylsphingosine, ether-linked diglycerides, ether-linked phosphatidic acidsand sphinganines.
 10. The intraluminal system of claim 9, wherein saidcompound is ceramide or a derivative thereof, that contains a 2-10carbon short-chain fatty acid at SN-2 position.
 11. The intraluminalsystem of claim 10, wherein the ceramide or derivative thereof is aC₆-ceramide.
 12. A method of preventing and/or treating hyperplasia at asite in a body lumen, comprising administering to said site agrowth-arresting, lipid-derived bioactive compound which inhibitsphosphorylation of a growth factor-induced extracellular signalregulated kinase (ERK) and/or a protein kinase B (PKB).
 13. The methodof claim 12, wherein said growth-arresting, lipid-derived bioactivecompound is selected from the group consisting of ceramide orderivatives thereof, dimethyl sphingosine, ether-linked diglycerides,ether-linked phosphatidic acids and sphinganines.
 14. The method ofclaim 13, wherein said growth-arresting, lipid-derived bioactivecompound is ceramide or a derivative thereof, that contains a 2-10carbon short-chain fatty acid at SN-2 position.
 15. The method of claim14, wherein the ceramide or derivative thereof is a C₆-ceramide.